Fidaxomicin Tied to Lower C difficile Recurrence in Immunocompromised Patients
Presented at MAD-ID 2025, Natt Patimavirujh, PharmD, supports fidaxomicin over vancomycin for high-risk groups, including transplant and chemotherapy patients.
At MAD-ID 2025, Natt Patimavirujh, PharmD, PGY-2 infectious diseases pharmacy resident at Tampa General Hospital, presented a single-center retrospective study demonstrating that fidaxomicin was associated with significantly lower recurrence rates of Clostridioides difficile infection (CDI) compared to oral vancomycin in immunocompromised patients, including solid organ transplant recipients and patients undergoing active chemotherapy.
The study included adult inpatients treated between January 1, 2022, and April 30, 2024, who were receiving immunosuppressive therapy and treated with either fidaxomicin (n=38) or oral vancomycin (n=30) for CDI. The primary outcome measured was CDI recurrence within 28 days of treatment completion. Secondary outcomes included 90-day recurrence, CDI-related hospital readmission, hospital length of stay, and outpatient medication cost.
At 28 days post-treatment, recurrence occurred in just 5% of patients in the fidaxomicin group compared to 30% of those treated with vancomycin (p=.006). At 90 days, recurrence rates were 15% versus 40%, respectively (p=.011). Readmissions related to CDI at 90 days also favored fidaxomicin (10% vs. 33%, p=.02).
Patimavirujh explained the rationale behind the study, “The 2021 IDSA/SHEA guidelines recommend fidaxomicin and oral vancomycin for treating C difficile infections, but they don’t really address treatment specifically for immunocompromised patients,” he said.
“At Tampa General, we focused on two high-risk immunosuppressed groups: solid organ transplant patients and patients receiving active chemotherapy. Tampa General is a major transplant center—ranked number one in transplant volume in the US—so this population is highly relevant to us.”
Highlighting the clinical implications, he continued, “Even though the guidelines don’t differentiate between these agents for immunocompromised patients, upfront use of fidaxomicin could reduce overall costs by preventing recurrences and readmissions in this high-risk group.”
The findings also support changes already underway at Tampa General Hospital, “Fidaxomicin used to be restricted and only used for patients who failed vancomycin,” Patimavirujh noted. “But in June 2023, we removed that restriction for high-risk patients—specifically those with solid organ transplants or on active chemotherapy. Our study supports this change and might encourage other institutions to consider adding fidaxomicin to their formularies for similar populations.”
Although, barriers to wider adoption remain—primarily cost, “Clinically, both drugs are effective against C. difficile, but fidaxomicin has narrower spectrum activity and spares the gut microbiome more than vancomycin,” he said. “That results in fewer recurrences, which is a big advantage. But the barrier isn’t efficacy—it’s cost. A 5–10 day outpatient course of fidaxomicin can cost over $3,000.”
He added that in cases of recurrence, hospitalization costs can easily exceed $15,000—making upfront investment in fidaxomicin potentially more cost-effective in the long run.
“Fidaxomicin was approved as a generic in January 2023, so we hope prices will begin to come down,” he said. To address cost-related barriers in the meantime, Tampa General Hospital has implemented access strategies. “We’ll initially dispense fidaxomicin and, if it’s not covered by insurance, we may switch to vancomycin PO,” Patimavirujh explained. “We also have a foundation clinic that helps patients apply for financial support—sometimes covering the full cost of fidaxomicin if they qualify.”
